Here are some pictures of my first year Centennial hops growing out of a pot. It has about 40 cones on it. I can't wait to harvest them and brew with them I am sure when I weigh them that it won't come out to much.

I fertilized them with comfrey that is growing from my yard. I just cut comfrey leaves and lay them in the pot with rocks on top of the leaves to prevent them from being blown away by the wind.

I have no clue if I am over or under-fertilizing, but I figure that comfrey leaves would be a slow release form of fertilizing so I don't worry about it too much.

You'll likely see some movement in early April. I find some varieties come up earlier than others (for instance, Cascades tend to be earlier than Chinook for me). I feel like when they start going is a product of how cool things stay in early spring, with soil temperatures raising, and the nighttime lows becoming warmer, as the major influencing factors.

The warm shot of weather we had the last couple weeks didn't get my hops moving but I had a blackberry bush that was confused about what season we were in.

You could take a look-see if you're really nervous. You can identify rhizomes with the new growth buds/tips fairly easily. I'd take that plant out of the pot in the next month or two and divide it into several more rhizomes and plant them, in something larger. More soil volume tends to translate into more vigorous growth and more harvested hops. An eight gallon pot is definitely limiting to even a first year plant, in my opinion. If you're stuck on growing them in containers, see if you can source a 24" or bigger nursery box (like the ones trees and palms tend to be planted in) or a half wine/whiskey barrel makes a good one, too. I find that you have to water hops more in containers but you can control their growing environment better, especially if there's a lot of root competition from mature trees/shrubs, and so on.